(Bi2Sr2Ca3Cu4O12+&dgr;)1(Bi2Sr2CaCu2O8+&dgr;)1superlattice films synthesized by sequential radio frequency magnetron sputtering on MgO substrates were studied by x‐ray diffraction method, Rutherford backscattering technique, magnetization measurements and Hall effect experiments. Superconducting transition temperature observed in the (Bi2Sr2Ca3Cu4O12+&dgr;)1(Bi2Sr2CaCu2O8+&dgr;)1superlattice films (55–58 K) was higher than those of Bi2Sr2Ca3Cu4O12+&dgr;(40–47 K) and Bi2Sr2CaCu2O8+&dgr;(50–52 K) single phase films. The results suggest that optimum carrier concentration is achieved in CuO2layers in the superlattice films by charge transfer from the overdoped Bi2Sr2CaCu2O8+&dgr;units to the underdoped Bi2Sr2Ca3Cu4O12+&dgr;units. ©1996 American Institute of Physics.